I want to use some sensors using CANbus interface. I noticed that there are simple interface ICs for electrical signals but what about the protocol and such. There are even larger chips, but are they needed.

By the way, searching for "can bus" is useless, I find results as "able"

You will also find CAN bus info at avrfreaks, like this one http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&t=117257A shield, https://www.sparkfun.com/products/10039A project, http://www.openhardwarehub.com/projects/40-Arduino-CAN-BUS-OBD-Gas-GaugeTutorial, http://www.jayconsystems.com/tutorial/canbus/